Perovskite-type La2Ti2O7 mesoporous photocatalyst

Crystalline particles of mesoporous La2Ti2O7, a perovskite-type material, were prepared by hydrothermal synthesis at 210°C in the presence of structure directing agent. Crystallization and simultaneous sintering occurred in the time course of the hydrothermal treatment, resulting in the improvement in crystallinity with a sacrifice of the decrease in surface area. The photocatalytic property was evaluated by hydrogen evolution from water with methanol sacrificial agent. The increase and the decrease of the material in crystallinity and surface area were responsible for the photocatalytic activity: the activity was improved by crystallization but the concurrent decrease in surface area (increase in size) of crystalline particles was disadvantageous. A homogeneous mixture of La and Ti oxide with amorphous inorganic network was hydrothermally crystallized at low temperatures to a perovskite-type La2Ti2O7. The small La2Ti2O7 particles with high crystallinity showed a potential as a photocatalyst for H2 evolution. [Display omitted] ► Crystalline mesopourous La2Ti2O7 was prepared. ► Hydrothermal treatment encouraged low temperature crystallization. ► Small crystalline domain was advantageous to a photocatalytic reaction.